This invention relates to a cap for preventing ingress of dust, water or the like into a bleed screw normally closing a bleed passage formed in a body of hydraulic component such as a master cylinder, wheel cylinder, actuator or the like.
Conventionally, the bleed screw is mounted on the body of the hydraulic component with a portion thereof projecting to the outside of the body, and only the head portion thereof wherein one end of bleed hole opens is covered by a cap having a generally cup-shaped form. Thus, the portion projecting to the outside and not being covered by the cap is exposed to the atmosphere and suffers from corrosion or the like according to dust or water accumulating thereon. Further, water or the like will ingress through the screw-threaded portion of the bleed screw into the valve portion, thus causing such portions to rust so that loosening the bleed screw during a bleeding operation will become difficult and breakage failure of the bleed screw or the screw-threaded portion of the hydraulic component will sometimes occur upon loosening the bleed screw.